You should be able to install the game to your computer from the disc. Then, make sure the game is patched to version 1.00b. (you can tell from the title screen) After that, download and install the english patch. It should be a .exe file, and make sure you put the patch in the same folder PCB is in.
Now I would say to download the english patch off of Touhou Wiki but it doesn't look like it's there right now. I could host mine as an exe file if you like up on mediafire.